The purpose of this project is to define the preliminary steps in steroid hormone action. In particular, a line of glucocorticord-responsive rat hepatoma tissue culture cells will be used to look at: 1) steroid-receptor binding site interactions; 2) effects of steroid binding on receptor conformation; 3) the nature of "activation" of receptor-steroid complexes, and 4) the nuclear binding of activated receptor receptor-steroid complexes.